The “+ New” button, to create a new notebook, seems like a link, but is not. Therefore, there is no way to create a notebook in a new tab (using Ctrl+Click for example). Maybe transform it to a link, or make it clearer it is a button.
This has been fixed! You can now go to
/new to create a new notebook:
If you commit any changes (e.g., Shift-Enter), your notebook will be saved to drafts automatically.